531131515021 has 4 divisors (see below), whose sum is σ = 531228460000. Its totient is φ = 531034570044.

The previous prime is 531131515009. The next prime is 531131515093. The reversal of 531131515021 is 120515131135.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 531131515021 - 2¹⁵ = 531131482253 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (531131815021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 48464271 + ... + 48475228.

It is an arithmetic number, because the mean of its divisors is an integer number (132807115000).

Almost surely, 2^531131515021 is an apocalyptic number.

It is an amenable number.

531131515021 is a deficient number, since it is larger than the sum of its proper divisors (96944979).

531131515021 is an equidigital number, since it uses as much as digits as its factorization.

531131515021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96944978.

The product of its (nonzero) digits is 2250, while the sum is 28.

Adding to 531131515021 its reverse (120515131135), we get a palindrome (651646646156).

The spelling of 531131515021 in words is "five hundred thirty-one billion, one hundred thirty-one million, five hundred fifteen thousand, twenty-one".